Railway track ballast tamping machine



Sept. 9, 1969 G. SAUTEREL 3,465,688

RAILWAY TRACK BALLAST TAMPING MACHINE Filed Oct. 2, 1967 2 Sheets-Sheet 1 INVENTOR 6554/60 SAUTEEEL BY gmdzxwum.

ATTORNEYS Sept. 9, 1969 e. SAUTEREL RAILWAY men BALLAST mama moms 2 Sheets-Sheet 2 Filed Oct. 2, 1967 INVENTOR, smzo 5407525 a W3 fimfl 3 W J1 E E M ami ifiwfi iv 5 53%; i

ATTORNEYS United States Patent 3,465,688 RAILWAY TRACK BALLAST TAMPING MACHINE Gerard Sauterel, Pully, Switzerland, assignor to Matisa Materiel Industriel S.A., Crissier, near Lausanne, Switzerland, a corporation of Switzerland Filed Oct. 2, 1967, Ser. No. 672,088 Claims priority, application Switzerland, Oct. 6, 1966, 14,430/ 66 Int. Cl. E01b 27/00 US. Cl. 104-12 6 Claims ABSTRACT OF THE DISCLOSURE A railway track ballast tamping machine of the type comprising a plurality of tamping tools arranged to carry out simultaneous packing of the ballast beneath two successive crossties so that the ballast tamping machine can be forwardly displaced in one feed stroke through a distance approximately corresponding to the spacing of two crossties. The aforementioned plurality of tamping tools incorporate a first double tamping tool arrangement which opens and serves for carrying out a tamping operation between two successive crossties and a second double tamping tool arrangement which closes and serves for carrying out a tamping operation While straddling said two successive crossties. Further, means are provided for vibrating the working end portions of the tamping tools of the first double tamping tool arrangement so as to be in phase with one another and for also vibrating the working end portions of the tamping tools of the second double tamping tool arrangement to be also in phase with one another, but wherein the vibrational phases of the working end portions of the first double tampin tool arrangement are always opposite to the vibrational phases of the working end portions of the second double tamping tool arrangement.

BACKGROUND OF THE INVENTION The present invention relates to an improved railway track ballast tamping machine which is equipped with tamping tools arranged in pairs. These tamping tools penetrate into the ballast and then-considering each pair individuallymove in a plane towards one another which is parallel to the axis of the track, in order to compress the ballast beneath the crossties or sleepers.

When the first tamping machines were introduced into the market it was conceived to equip these machines with a plurality of pairs of tamping tools, in order to be able to simultaneously pack the ballast beneath a number of crossties.

Thus, for instance, the United States Patent 1,043,245, granted Nov. 5, 1912, taught a tamping machine having two groups of tamping tools which operate simultaneously and to both sides of two crossties. However, the two crossties which were simultaneously packed were not situated directly adjacent one another, which of necessity resulted in an irregular feed movement of the machine.

The United States Patent 2,497,682, granted Feb. 14, 1950 teaches the feature of lowering a tamping element in the intermediate space between two crossties, and wherein this tamping element provides a double tool which opens and the components of which move away from one another during the working movement. The inventive machine of this particular patent is equipped with a series of such type tools, in order to be able to simultaneously pack the ballast beneath a number of successive crossties.

Furthermore, the French Patent 1,423,462 also pertains ice to a multiple-tamping machine. It is equipped with two pairs of tamping tools for simultaneously packing two successive crossties, This machine is essentially manifested by the features that the tamping tools of both tamping groups and their work path in the longitudinal direction of the crossties are arranged to be mutually offset with respect to one another, in order to prevent that those tamping tools of each of both tamping groups, which penetrate back-to-back in the same intermediate space between two crossties, do not hinder one another during the working operation. As a result, compacting or packing of the ballast beneath the crossties occurs at one side, whereby the non-symmetry changes sides from crosstie to crosstie. Additionally, these tamping tools, which are subjected to jarring vibrations of fixed amplitude, but not of a clearly fixed or defined phase and frequency, must be arranged at a sufficient spacing from one another in order to eliminate any possible mutual contact. Consequently, there is a reduction of the useful working stroke as well as the formation of holes in the ballast bed owing to pushing in of the ballast stones during penetration of the tamping tools, so that this penetration is additionally rendered more difficult.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide an improved railway track ballast tamping machine which effectively overcomes the drawbacks of the prior art structures.

Another, more specific object of this invention rel-ates to an improved railway track ballast tamping machine which enables simultaneous packing of the track ballast betwen two succesive crossties of the railroad track, in that the inventive machine carries out in the ballast and at both sides of each of the two crossties a compactingand-vibrational movement, without however having to laterally displace the confronting tamping tools.

Still a further significant object of this invention pertains to an improved railway track ballast tamping machine which is extremely reliable in operation and capable of carrying out packing of the ballast beneath the crossties of a railroad track in an extremely efficient and economical manner, while operating at high speeds.

Now, in order to implement these and still further objects of the invention which will become more readily apparent as the description proceeds, the inventive railway track ballast tamping machine is of the type which possesses a plurality of tamping tools which are arranged in such a manner that it is possible to simultaneously pack the ballast beneath two successive crossties, so that the ballast tamping machine can be forwardly displaced in one feed stroke through a distance corresponding to donble the spacing of two crossties. According to an important aspect of the invention, the plurality of tamping tools incorporate a first double tamping tool arrangement which opens and serves for working between two successive crossties and the working ends of the tamping tools thereof are subjected to jarring vibrations which are in phase with one another. Additionally, the aforesaid plurality of tamping tools incorporates a second double tamping tool arrangement which closes and serves for carrying out a tamping operation while straddling the aforementioned two successive crossties and wherein the working end portions of the tamping tools of said second double tamping tool arrangement are subjected to jarring vibrations which are in phase with one another. However, it is to be understood that the phases of the jarring vibrations of the working end portions of the first double tamping tool arrangement which opens always are opposed to the phases of the jarring vibrations of the work- 0 ing end portions of the tamping tools of the second double tamping tool arrangement which closes.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood, and objects other than those set forth above, will become apparent, when consideration is given to the following detailed description thereof, Such description makes reference to the annexed drawings wherein:

FIGURE 1 is a side view of a preferred embodiment of inventive railway track ballast tamping machine showing those components which are directly necessary for fully comprehending the underlying concepts of the present invention;

FIGURE 2 is a fragmentary cross-sectional view of the inventive tamping machine depicted in FIGURE 1, taken along the line 2-2 thereof;

FIGURE 3 is a cross-sectional view of a detail of the inventive tamping machine depicted in FIGURES 1 and 2;

FIGURE 4 schematically illustrates in plan view the position of the tamping plates or bits and their direction of movement during a certain period of time; and

FIGURE 5 again shows the same schematic plan view representing the operation of the inventive tamping machine, but for a different period of time.

DESCRIPTION OF THE PREFERRED EMBODIMENT Describing now the drawings, it is to be understood that in FIGURE 1 there is illustrated the forward portion of a railroad track vehicle V together with its rigid frame unit 1 and its forward axle 2. The track along which the vehicle V travels and which is to be tamped is represented by the track rail 3, the crossties 4 and the ballast bed 5. The illustrated tamping tools 15, 16, 17 and 18 are mounted in overhanging fashion at the front region of the railroad track vehicle V. By inspecting FIGURES 1 and 2 there will be recognized two respective groups of such tamping tools which are arranged at both sides of the associated track rail 3. The other groups of tamping tools which work at the second track rail do not have any bearing upon the operation of the first groups of tamping tools which are illustrated in the drawings, and since their representation is not necessary for understanding the inventive concepts they have been conveniently omitted from the drawings.

The groups of tamping tools 15, 16, 17, 18 for a given track rail, such as the rail 3, are mounted at a vertically displaceable tamper head or box 7. The latter is guided at two guide columns 8 and is moved vertically up and down through the agency of a suitable drive, such as the hydraulic cylinder drive unit 9. The cylinder drive unit 9 includes a cylinder housing 911 which is rigidly connected with the vehicle frame 1 and its piston rod 10 is operatively connected via a hinge joint 6 with the tamper head 7.

Furthermore, it is to be understood that the tamping tools 15, 16, 17 and 18 for the illustrated track rail 3 are arranged in parallel planes, wherein two similar groups are always located at each side of such track rail. The tamping tools which are arranged in each of these four planes possess respective tamping plates or bits 11-14 which are welded or otherwise connected to the respective ends of the tool shafts 15a18a of the tamping tools 15-18 respectively, The tool shafts 15a, 16a, 17a and 18a are, in turn, detachably mounted at the tool carriers or supports 19, 20, 21 and 22 respectively.

Continuing, it should be understood that the tamping tools 15 and 18 collectively form a so-called double tamping tool arrangement which closes, in other words, one which packs the ballast in that it closes, whereby the tamping tools 15 and 18 carry out a movement towards one another. As will be apparent by inspecting FIGURE 1, these tamping tools 15, 18 work in straddling fashion over two successive crossties 4. On the other hand, the

tamping tools 16 and 17 collectively form a double tamping tool arrangement which opens, in other words, one which packs the ballast in that it opens, and wherein the tamping tools 16, 17 carry out a movement away from one another. This opening double tamping tool arrangement 16, 17 serves to operate in the intermediate space or compartment between the two crossties 4 which were previously considered in connection with the other tamping tools 15, 18. The ballast beneath the one crosstie will be packed or compressed due to the cooperation of both tamping tools 15 and 16, whereas the ballast beneath the other crosstie will be packed or compressed due to the cooperation of both tamping tools 17 and 18.

The previously considered tamping tool carriers or supports 19, 20, 21 and 22 possess the configuration of simple pivotal levers which are mounted for rotation about the corresponding pivot pins or bolts 23, 24, 25 and 26 respectively. Each pivot pin 23, 24, 25 and 26 is seated upon a respective travelling nut member 27, 28, 29 and 30, which are displaceably guided in the lengthwise direction of the track vehicle V upon a guide rod means 31. The nut member 27 is displaced in longitudinal or lengthwise direction by means of a threaded spindle 32, the nut member 28 in similar manner but by means of a threaded spindle 33, the nut member 29 by means of a threaded spindle 34, and finally the nut member 30 by means of a threaded spindle 35. The four threaded spindles 32, 33, 34 and are aligned in a straight line which is in parallelism with the guide rod 31. Furthermore, as generally indicated in FIGURE 1, the sense of direction of the threading changes from spindle to spindle. However, the direction of rotation is the same for all four of these spindles 32, 33, 34 and 35. Furthermore, the threaded spindles 33 and 34 form a coherent or unitary member, whereas detachable couplings 47 and 48 are provided between the threaded spindles 32 and 33 and the threaded spindles 34 and 35 respectively. These coupling members or units 47 and 48, which are of standard construction, will be considered in greater detail hereinafter during the consideration of FIGURE 3.

The required driving energy necessary for rotating the threaded spindles 32, 33, 34 and 35 is delivered by two drive units, typically hydraulic motors 36 and 37. These hydraulic motors 36 and 37 are mounted at the frame of the tamper head 7. At the free shaft end of each of the drive motors 36 and 37 there is seated a sprocket gear or chain wheel 40 and 41 respectively, for driving two respective link chains 44 and respectively at each end of the tamper head 7, as best shown by referring to FIG- URE 1. The chain member 44 drives a chain wheel or sprocket gear 42 which is seated upon the free end of the spindle 32 and further drives a second chain wheel 43 which is seated at the free end of a spindle 32a (FIGURE 2) which is similar to the spindle 32. This further spindle 32a is located at the other side of the track rail 3. In similar manner, the chain 45 drives two further sprocket gears or chain wheels for the driving of two similar spindles. Of these last-mentioned spindles there is only visible in the drawings the spindle member 35 together with its sprocket wheel 46.

FIGURE 3 illustrates details of the previously considered detachable coupling units 47 and 48, wherein, it will be recalled, that the one coupling unit 47 serves to operatively connect both of the spindles 32 and 33, and the other coupling unit 48, which is identical to the first coupling unit 47, serves to operatively interconnect both of the spindles 34 and 35. Since both of these coupling units 47 and 48 are identical, FIGURE 3 will be directed to the coupling unit 47 associated with the spindles 32 and 33. More precisely, in FIGURE 3 the coupling housing 51, which is fixedly connected with the frame of the tamper head 7, is shown in section, and there is further illustrated a respective portion of each of both spindles 32 and 33. Mounted at the end of the spindle 32 is a gear 52 and at the end of the other spindle 33 a further gear 53,

wherein both these gears 52 and 53 are located adjacent one another in the coupling housing 51, as shown. These gears 52 and 53 are completely similar to one another in diameter and also in the number of teeth which they possess, so that an internally toothed sleeve member 54 can be axially displaced over both gears 52 and 53, in order to optionally provide a fixed connection between both of the threaded spindles 32 and 33 or to bring about a complete disconnection from one another. Further, it will be recognized that the housing 51 is pierced by a circular rod member 55 which, in turn, carries a finger or projection 56 engageable with a circular or annular groove 57 formed at the sleeve member 54. Additionally, the circular rod member 55 is equipped with a manual lever 58 permitting axial displacement of this rod member 55, as will be evident by referring to FIGURE 3.

In the representation of the coupling unit shown in FIGURE 3 this coupling unit is in its released or disengaged position. Thus, the spindle member 33 is not driven and the threaded nut member 28 remains in its spatial position. Now, in order to operatively interconnect both of the spindle members 32 and 33 with one another, the handle or manual lever 58 is displaced towards the right of FIGURE 3, whereby the sleeve member 54 simultaneously is brought into engagement with the gear 52 and the other neighboring gear 53, so that both of these gears 52, 53 rotate in unison.

Owing to the provision of both of the hydraulic drive motors 36 and 37, which can be placed into operation individually, and by virtue of the disengageable or detachable couplings 47 and 48 it is possible to carry out a number of different operational possibilities for the previously described tamping tools. During the primary working technique which is generally carried out, both of the hydraulic drive motors 36 and 37 are placed in operation and drive the chains 44 and 45. Furthermore, both of the coupling members 47 and 48 are engaged. The outer, closing tamping tools 15 and 18, together with their tamping plates or bits 11 and 14 respectively, carry out a mutual movement towards one another and away from one another. During the same period of time, the inner, opening tamping tools 16 and 17, together with their tamping plates or bits 12 and 13 respectively, carry out a corresponding reversed movement away from one another and towards one another. In this manner, the ballast is simultaneously packed or compressed beneath two successive crossties 4. After expiration of a complete tamping cycle the track vehicle V advances through a distance which corresponds to twice the distance or spacing of the crossties 4.

In accordance with another operating technique both of the coupling units 47 and 48 are disengaged. Both of the hydraulic drive motors 36 and 37 drive both of the threaded spindles 32 and 35 respectively, whereas the threaded spindles 33 and 34 are not rotated. The outer tamping tools 15 and 18, together with their tamping bits 11 and 14 respectively carry out their mutual closing movement towards one another, and the inner tamping tools 16 and 17 together with the tamping bits 12 and 13 respectively and the tool shafts 16a and 17a respectively, form a blocking wall against the pressure of the ballast which is produced by the movement of the outer tamping plates or bits 11 and 14.

The detachable coupling units 47 and 48 also permit fixing of the position of the outer tamping plates or bits 11 and 14 with respect to the inner tamping bits 12 and 13, and, thus, allow for adjustment of the opening width of the outer tamping tools 15, 18 to the different spacing between the crossties which appear at the railroad network.

In order to render possible the penetration of the tamping tools 15, 16, 17 and 18 into the ballast 5 and to enable compacting or packing thereof, these tamping tools, just as with the known tamping tools, are subjected to jarring vibrations which occur in the same planes as the previously considered working movements of the tamping tools.

The jarring vibrations are generated by a nonvisible shaft member which is equipped with eccentric plates or discs 59 which are driven by suitable nonillustrated hydraulic motor means or the like. The eccentric disks 59 are connected on the one hand by means of a coupling rod 60 with the tool carrier or support 21 and, on the other hand, via a further coupling rod 61 with the tool carrier or support 22, as shown in FIGURE 1. Furthermore, the eccentric disks 59 are keyed to the shaft in offset relationship with respect to one another in such a manner that the pivot points 62 and 63 carry out at both of the tool supports 21 and 22 oscillatory or vibrational movements of opposite phase.

Additionally, it will be seen that the pivot point 62 is connected with a further pivot point 64 at the tool support 20 by means of a coupling rod 65. The previously mentioned pivot points 62 and 64 serve, on the one hand, as (vibrating )fixed points for the tool supports 20 and 21 for their opcning-and-closing movement and, on the other hand, transmit the jarring vibrations in phase to the tool supports 20 and 21.

Furthermore, it will be seen that the tool support or carrier 22 is connected via a coupling rod 66 with the tool support 19. More precisely, this coupling rod 66 forms together with the tool support 22 a pivot joint 67 and forms together with the second tool support 19 a pivot joint 68. Accordingly, the coupling rod 66 now transmits the jarring vibrations in phase from the tool support 22 to the tool support 19. In so doing, the pivot joint 68 serves as (vibrating) fixed point for the tool support 19 for its closing-and-opening movement.

FIGURE 4 schematically illustrates in plan view the momentary motion condition of the tamping plates or bits 11, 12, 13, and 14 during a predetermined period of time at the beginning of a tamping cycle according to the first described mode of operation. The chain-dot line 70 schematically represents the longitudinal axis of the track rail 3. The double-lined arrows designated by reference numeral 71 represent the direction of motion of the tamping bits during the operating or work movements, and the short, simple arrows 72, 73 represent the direction of motion of the vibrations imparted to the tamping bits, and specifically always for the same predetermined period of time. In this context, it should also be understood that the arrows 72 represent the movements of the outer tamping bits 11 and 14 and the arrows 73 the movements of the inner tamping bits 12 and 13.

FIGURE 5 schematically represents a different condition for the movement of the tamping tools at a period of time which is still at the beginning of the tamping cycle, however wherein the phase of the vibrations is displaced by one half of the period of the oscillations or vibrations with respect to the condition depicted in FIGURE 4.

It should be apparent from the schematic motion diagrams that the momentary direction of sense or movement represented by the arrows 72, of the vibrations of the tamping bit or plate 11 is always opposite (opposed in phase) to the direction of movement, represented by arrows 73, of the tamping bit 12. The same conditions prevail for the tamping plates or bits 13 and 14. On the other hand, it should also be apparent that the tamping plates or bits 12 and 13 always oscillate or vibrate in the same sense, that is to say they are in phase with one another.

This provides the advantage that the tamping plates or bits 12 and 13 of the inner, opening tamping tools 16 and 17 respectively, can be mounted quite close to one another, that is to say, up to mutual contact at the begin ning of the tamping cycle, without there existing the danger that thetamping bits or the tamping tool shafts of both tamping tools 16 and 17 will impact against one another. Such impact could result in rupture of a tamping tool or breakdown of the associated drive mechanism or could possibly bring about grinding of the stones clamped between the tamping bits during lowering of the tamping tools into the ballast. As a result, there does not exist any necessity for laterally oifsetting or displacing the tamping tools, and the work path of the tamping tools nonetheless begins in the center or middle of the intermediate space between two crossties 4. As is known, with the conventional tamping machines, which are based upon the principle of vibrating and compressing or compacting, the work path of the tamping tools likewise begins at the center of the intermediate space of the crossties. The quality of the tamping work is thus just as good with the tamping machine of the invention as with the standard tamping machines, but the tamping operation is, however, carried out with almost twice as large an efiiciency or speed. Owing to the very close approach of the opening tamping tools 16 and 17 there is prevented the danger of pressing in the ballast during penetration of these tamping tools into the ballast, and, therefore, there is also prevented the danger that the tamping tools will leave a hole in the ballast when they are withdrawn.

While there is shown and described a present preferred embodiment of the invention, it is to be distinctly understood that the invention is not limited thereto.

What is claimed is:

1. A railway track ballast tamping machine comprising, in combination:

(a) a plurality of tamping tools arranged to carry out simultaneous packing of the ballast beneath two successive crossties so that the ballast tamping machine can be forwardly displaced in one feed stroke through a distance approximately corresponding to double the spacing of two crossties;

(b) said plurality of tamping tools incorporating a first double tamping tool arrangement which opens and serves for carrying out a tamping operation between two successive crossties;

(c) said plurality of tamping tools further incorporating a second double tamping tool arrangement which closes and serves for carrying out a tamping operation while straddling said two successive crossties;

(d) each of said plurality of tamping tools defining said first and second double tamping tool arrangement having a respective working end portion; and

.(e) means for vibrating said working end portions of said first double tamping tool arrangement so as to be in phase with one another and for vibrating said working end portions of said second double tamping tool arrangement to be also in phase with one another, but wherein the vibrational phases of said working end portions of said first double tamping tool arrangement are always opposite to the vibrational phases of the working end positions of said second double tamping tool arrangement.

2. A railway track ballast tamping machine as defined in claim 1, further including means for selectively opening and closing said first double tamping tool arrangement, said opening and closing means comprising two aligned threaded spindles having opposite threading and arranged along the same axis and rigidly connected with one another, two threaded nut members each of which is arranged at one of said threaded spindles and rigidly connected with one of the tamping tools of said first double tamping tool arrangement in order to open and close said first double tamping tool arrangement in accordance with the rotational sense of said two threaded spindles.

3. A railway track ballast tamping machine as defined in claim 2, further including means for selectively opening and closing said second double tamping tool arrangement, said opening and closing means comprising two threaded spindle members having opposite threading and which are likewise aligned along the same axis as the aforesaid two spindles, each of said threaded spindle members being arranged as an extension of one of said threaded spindles of said opening and closing means of said first double tamping tool arrangement, two further threaded nut members, each of which is arranged at one of said threaded spindle members and rigidly connected with one of the tamping tools of said second double tamping tool arrangement in order to open and close said second double tamping tool arrangement in accordance with the rotational sense of said two threaded spindle members.

4. A railway track ballast tamping machine as defined in claim 1, wherein said vibrating means comprises a vibrating mechanism arranged between one of the tamping tools of the first double tamping tool arrangement and one of the tamping tools of the second double tamping tool arrangement, means for mechanically coupling said vibrating mechanism with both of the aforesaid one tamping tools in order to impart thereto synchronous vibrations of opposite phase, a respective rigid coupling element for interconnecting the tamping tools of each double tamping tool arrangement with one another, in order to generate synchronous vibrations which are in phase between the tamping tools of the same double tamping tool arrangement.

5. A railway track ballast tamping machine comprising, in combination:

(a) a plurality of tamping tools arranged to carry out simultaneous packing of the ballast beneath two successive crossties;

(b) said plurality of tamping tools incorporating a first double tamping tool arrangement which serves for carrying out a tamping operation between two successive crossties;

(c) said plurality of tamping tools further incorporating a second double tamping tool arrangement which serves for carrying out a tamping operation while straddling said two successive crossties;

(d) each of said plurality of tamping tools defining said first and second double tamping tool arrangements having a respective working end portion;

(e) means for selectively opening and closing said tamping tools of said first and second double tamping tool arrangements; and

(13') means for vibrating said working end portions of said first double tamping tool arrangement so as to be in phase with one another and for vibrating said working end portions of said second double tamping tool arrangement to be also in phase with one another, but wherein the vibrational phases of said working end portions of said first double tamping tool arrangement are always opposite to the vibrational phases of the working end portions of said second double tamping tool arrangement.

'6. A railway track ballast tamping machine comprising in combination: a plurality of tamping tools arranged to carry out simultaneous packing of the ballast beneath two successive crossties so that the ballast tamping machine can be forwardly displaced in one feed stroke through a distance approximately corresponding to double the spacing of two crossties; said plurality of tamping tools incorporating a first double tamping tool arrangement which opens and serves for carrying out a tamping operation between two successive crossties; said plurality of tamping tools further incorporating a second double tamping tool arrangement which closes and serves for carrying out a tamping operation while straddling said two successive crossties; each of said plurality'of tamping tools defining said first and second double tamping tool arrangement having a respective working end portion; and means for vibrating said working end portions of said first double tamping tool arrangement so as to be in phase with one another and for vibrating said working end portions of second double tamping tool arrangement to be also in phase with one another, but wherein the vibrational phases of said working end portions of said first double tamping tool arrangement are always opposite to the vibrational phases of the working end positions of said second double tamping tool arrangement; means for selectively opening and closing said first double tamping tool arrangement, said opening and closing means comprising two aligned threaded spindles having opposite threading and arranged along the same axis and rigidly connected with one another, two threaded nut members each of which is arranged at one of said threaded spindles and rigidly connected with one of the tamping tools of said first double tamping tool arrangement in order to open and close said first double tamping tool arrangement in accordance with the rotational sense of said two threaded spindles; means for selectively opening and closing said second double tamping tool arrangement, said opening and closing means comprising two threaded spindle members having opposite threading and which are likewise aligned along the same axis as the aforesaid two spindles, each of said threaded spindle members being arranged as an extension of one of said threaded spindles of said opening and closing means of said first double tamping tool arrangement, two further threaded nut members, each of which is arranged at one of said threaded spindle members and rigidly connected with one of the tamping tools of said second double tamping tool arrangement in order to open and close said second double tamping tool arrangement in accordance with the rotational sense of said tool threaded spindle members; said machine further including two coupling devices for selectively rigidly interconnecting or releasing the connection between one of said threaded spindle members associated with said second double tamping tool arrangement and the neighboring threaded spindle associated with said first double tamping tool arrangement, the threading of each two neighboring threaded spindle elements being opposite to one another.

References Cited UNITED STATES PATENTS 1,048,797 12/1913 Bissell 104-12 2,052,943 9/1936 Scheuchzer 104-12 3,357,366 12/1967 Plasser et a1 10412 3,343,497 9/1967 Stewart 10412 3,372,651 3/1968 Plasser et a1 10412 3,380,395 4/1968 Plasser et al 104-12 ARTHUR L. LA POINT, Primary Examiner R. A. BERTSCH, Assistant Examiner 

